The increasing use of solar systems to provide space heating and domestic hot water is accompanied by a need for adequate facilities for storing heat obtained from solar collector panels during daylight hours. New buildings can be specially designed to include heat storage facilities such as hot water storage pools, rock-pile storage areas, etc; but a serious problem arises in connection with efforts to install solar heating systems in previously constructed buildings which were not designed with such installations in mind. For instance, access to ground-level or basement rooms of an existing building is generally had through a door or a window of a size which would not admit a large-volume water storage tank. Moreover, once in the building, the installers of the system usually prefer to install the tank against an existing wall, and often in the corner of a room against two adjoining walls, thereby making access to the outside corners of the tank inaccessible for purposes of assembly. Such a tank, besides being of large volume, must be of heavy construction to support the weight of the stored water, and must have thick thermally insulated walls. Moreover, access to the tank which is preferably had through its top portion to preserve optimum leak-proof integrity, may be limited by a low ceiling in the room. The above features are all considered important in the design of a tank having sufficient versatility to permit its assembly in almost all locations where it is to be installed in an existing building.
The prior art shows several knock-down containers which come apart as six panels, which panels have insulated double walls and are mutually secured together by interfitting brackets pinned together on the outside of the container, as taught in U.S. Pat. Nos. 3,007,597 and 3,093,259 issued to Morrison and used to contain and insulate dry or frozen products.
There are also a number of membrane-lined cryogenic containers having frame-constructed side walls as shown in U.S. Pat. No. 3,477,606 to Schwendtner and lined with a membrane liner as shown in U.S. Pat. No. 3,827,135 to Yamamoto, wherein access is gained through the top of the tank. There are, of course, many containers openable by raising a top panel which, when closed, seals by a peripheral gasket to the top edges of the tank walls.
Copies of the above mentioned patents are filed herewith in lieu of a Prior Art Statement.